Typically, three-dimensional image display may be achieved based on the principle of stereo-vision via an observer's eyes. Specifically, in three-dimensional image display, the observer's left and right eyes view two different two-dimensional images, respectively. Two different two-dimensional images are transmitted to the brain simultaneously, giving the impression of a real 3-dimensional image. Recently, three-dimensional display apparatuses have become a focus of research in display technology. For example, three-dimensional view eyeglasses have been developed for generating three-dimensional (3D) image when viewing movies and televisions.